/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.algebra.op;

import java.util.List;
import java.util.Objects;

import org.apache.jena.sparql.algebra.Op;
import org.apache.jena.sparql.algebra.OpVisitor;
import org.apache.jena.sparql.algebra.Transform;
import org.apache.jena.sparql.core.VarExprList;
import org.apache.jena.sparql.expr.ExprAggregator;
import org.apache.jena.sparql.sse.Tags;
import org.apache.jena.sparql.util.NodeIsomorphismMap;

public class OpGroup extends Op1
{
    private VarExprList groupVars;
    private List<ExprAggregator> aggregators;

    public static OpGroup create(Op subOp, VarExprList groupVars, List<ExprAggregator> aggregators) {
        return new OpGroup(subOp, groupVars, aggregators);
    }

    public OpGroup(Op subOp, VarExprList groupVars, List<ExprAggregator> aggregators) {
        super(subOp);
        this.groupVars = groupVars;
        this.aggregators = aggregators;
    }

    @Override
    public String getName()                     { return Tags.tagGroupBy; }
    public VarExprList getGroupVars()           { return groupVars; }
    public List<ExprAggregator> getAggregators()  { return aggregators; }

    @Override
    public void visit(OpVisitor opVisitor)      { opVisitor.visit(this); }
    @Override
    public Op1 copy(Op subOp)                    { return new OpGroup(subOp, groupVars, aggregators); }

    @Override
    public Op apply(Transform transform, Op subOp)
    { return transform.transform(this, subOp); }

    @Override
    public int hashCode() {
        int x = getSubOp().hashCode();
        if ( groupVars != null )
            x ^= groupVars.hashCode();
        if ( aggregators != null )
            x ^= aggregators.hashCode();
        return x;
    }

    @Override
    public boolean equalTo(Op other, NodeIsomorphismMap labelMap) {
        if ( !(other instanceof OpGroup) )
            return false;
        OpGroup opGroup = (OpGroup)other;
        if ( !Objects.equals(groupVars, opGroup.groupVars) )
            return false;
        if ( !Objects.equals(aggregators, opGroup.aggregators) )
            return false;

        return getSubOp().equalTo(opGroup.getSubOp(), labelMap);
    }
}
